Machining process for production of titanium motor housing

Abstract

The present invention discloses a machining process for manufacturing a motor housing by using metal titanium, including the following machining steps: Calendar process is adopted, use stamping equipment to stamp the base of the titanium motor housing, apply lubricant on the surface of the die before stamping, and attach a lubricating film on the surface of metal titanium to be stamped; Calendar process is adopted, use stamping equipment to stamp the barrel-shaped titanium motor housing, apply lubricant on the surface of the die before stamping, and attach a lubricating film on the surface of metal titanium to be stamped, and after stamping, a barrel-shaped housing with a barrel depth to port diameter ratio of 1.2˜1.8:1 is obtained; Spray and cleanse the housing base obtained from stamping in S1 and the barrel-shaped motor housing obtained from stamping in S2; Assemble the housing base and the barrel-shaped housing obtained in S3 to form the motor housing product; Inspect the assembled motor housing obtained in S4.

Description

TECHNICAL FIELD[0001]This invention relates to the technical field of motor part production and machining, particularly a process for machining motor housing by using metal titanium.TECHNICAL BACKGROUND[0002]Characterized by light weight, high strength, having metallic luster, corrosion resistance, high / low temperature resistance, etc., titanium is an ideal stamping material for motor housing. However, due to its difficulty in forming and machining as well as high cost, there is no record of motor housing made of titanium in prior art. In the present stage, people cannot manufacture motor housing by using titanium.[0003]When a titanium alloy has a hardness of more than HB350, its machining and cutting is extremely difficult, and when its hardness is less than BH300, it can very easily stick to the cutters, also making cutting difficult. However, hardness of titanium alloy is only one of the reasons for the cutting and machining difficulties, what is more critical is the impact of th...

AI Technical Summary

Benefits of technology

[0011]An object of the present invention is to overcome the drawbacks existing in the prior art and provide a titanium motor housing machining process for manufacturing motor housings made of titanium metallic material by stamping method, which is characterized by simple machining process and high forming efficiency, and can be used for mass and high-efficiency production of titanium motor housings.

[0029]To allow for easy relief of the internal stress during machining of titanium, a further preferred embodiment is also characterized in that the tempering heat treatment in the said Step 1-5 is specifically as follows: First, subject the ideally contoured housing base or barrel-shaped motor housing to vacuum annealing at a temperature of 690° C.; Then hold the temperature for 2 hours; After temperature holding, naturally cool the housing base or barrel-shaped motor housing to the normal temperature in the vacuum furnace.

[0034]The present invention has the following advantages and favorable effects: the titanium motor housing machining process can be used to manufacture motor housing by using titanium, which can ensure a good product forming quality, improve the products consistency, fill up the blank in titanium motor housing manufacturing, improve the motor performance and extend the motor service life. Stamping process can be used for manufacturing motor housing by using metal titanium, which is characterized by simple machining process, high forming efficiency and allowing for high efficiency mass production.

Problems solved by technology

However, due to its difficulty in forming and machining as well as high cost, there is no record of motor housing made of titanium in prior art.

When a titanium alloy has a hardness of more than HB350, its machining and cutting is extremely difficult, and when its hardness is less than BH300, it can very easily stick to the cutters, also making cutting difficult.

However, hardness of titanium alloy is only one of the reasons for the cutting and machining difficulties, what is more critical is the impact of the combined chemical, physical and mechanical performances of titanium alloy itself on machinability.

(1) Small deformation coefficient: This is a remarkable characteristics of titanium in respect of cutting and machining, and the deformation coefficient is smaller than or close to 1. The slide and friction distance of swarf on the rake face of the cutter increases greatly, which accelerates the cutter wear and reduces the elongation.

(2) High cutting temperature: Since titanium alloys have a very small heat conductivity coefficient (only equivalent to ⅕˜ 1 / 7 of that of #45 steel), and the length of contact between the swarf and the rake face of the cutter is extremely short, heat produced during cutting cannot be easily conducted out and concentrates in the cutting zone and in a small area near the cutter edge, resulting in a very high cutting temperature. Under the same cutting condition, the cutting temperature can be twice that of #45 steel.

(3) Big unit area cutting force: The main cutting force is about 20% smaller than when cutting steel. Since the length of contact between the swarf and the rake face of the cutter is extremely short, the unit contact-area cutting force increases greatly, which can easily cause tipping. Meanwhile, due to a small elasticity modulus of titanium alloys, this can easily give rise to bending deformation under the action of radial force during machining, resulting in vibration, adding to tool wear and affecting the precision of parts and components. Therefore, the process system should have a good rigidity.

(4) Severe chilling phenomenon: Attributable to the high chemical activity of titanium, hard and crispy scales can be easily formed by absorbing O2 and N2 in the air at a high cutting temperature; Meanwhile, the plastic deformation during cutting operation may also cause surface hardening. Not only reducing fatigue strength of the parts and components, the chilling phenomenon can also aggravate tool wear, which is a very important characteristic demonstrated during titanium cutting.

(5) Easy tool wear: After processed by stamping, forging and hot rolling and other methods, hard and crispy uniform scales can be formed, which can easily cause tipping phenomenon, making hard scale cutoff the most difficult procedure in titanium alloy machining. Furthermore, since titanium alloy has a very high chemical affinity towards the materials of the tools, it is very easy to produce accretion wear to the tools under a high cutting temperature and a high unit area cutting force. During turning of titanium alloy, sometimes the wear on the rake face of the cutter is even more severe than flank face of the cutter; At a feed rate f0.2 mm / r, wear will occur on the rake face of the cutter; During finish turning and semi-finish turning by using hard alloy cutters, wear on the flank face of the cutter is more appropriate with VBmax<0.4 mm.

When it comes to milling, since titanium alloys have a very small heat conductivity coefficient, and the length of contact between the swarf and the rake face of the cutter is extremely short, heat produced during cutting cannot be easily conducted out and concentrates in the cutting deformation zone and in a small area near the cutter edge, as a result, a extremely high cutting temperature can be formed at the cutting edge during machining, which may greatly shorten the service life of the tools.

Machining of titanium is very difficult.

At present, cutting or mould pressing method is used, and since titanium cannot be cut at a low speed and it may be oxidized due to the excessive heat when cutting at high speed, titanium alloy products cannot be machined at ordinary machining center, while mould pressing can easily give rise to cracks.

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